I'm on the 4th burning season with an EFM that was painted with the POR-15. It hasn't been affected by the corrosiveness of the coal ash. What has happened is that the nice silver finish turned amber where it was affected by the heat. The front door is still silver and the inside is still hard as nails. The floor of the base still is hard and all there. They make a POR-20 that is a higher temp but it needs to be cured with 475 degree heat. It stays soft and scratches real easy untill it is cured.

Well here's the results.What I painted was the inside base (Ash Can Area) of my harman VF3000. After 3 heating seasons it held up reasonably well. It probably would have done better but at some pt between 2nd and 3rd season had a small leak in hot water coil and a puddle formed that I didnt notice and caused rust. Caused paint to lift from surface. Well...here I am again needing to paint. Probably not going with POR15 again mostly because of price. Considering rustoleum rusty metal primer and rustoleum. Anyone have any suggestions?

I removed mill scale from my Keystoker 90 when brand new and used POR manifold paint. I think the dust actually sticks to it, I would not do it again. There is a link about this I will try to find and post.